The invention essentially is a torso restraint system that provides an aircraft crewmember protection particularly against severe lateral forces as well as forward and backward forces while also allowing the crewmember to turn left or right and to bend forward or backwards in the seat during normal flight conditions.
Modern high performance fighter aircraft are capable of rapid roll accelerations as well as sophisticated flight maneuvers including direct side force. Severe stresses are placed on the pilot by such aircraft maneuvers. Frequently, modern aircraft are capable of aerial maneuvers which are beyond the tolerance of the human pilot. Consequently, many fighter aircraft and their pilots are lost as a result of pilot blackout.
Although there are a variety of restraint systems for pilots currently available, these restraint systems typically do not adequately address the problem of torso restraint from forces acting in a lateral direction with respect to the aircraft seat. Typically, prior art systems are designed to protect the pilot from acceleration or deceleration forces acting primarily in the forward or backward directions with respect to the aircraft seat.
Some pilot restraint systems incorporate straps which cross over the pilot's chest. In such prior art systems, the straps which are positioned across the pilot's chest are anchored to the sides of the seat. Since many pilot seats are wider than the torso of the pilot, the straps do not make full contact with the lateral portions of the pilot's torso. Thus, the straps still allow lateral movement of the pilot relative to the seat. Thus, the pilot's torso is allowed to build up speed (relative to the cockpit) between the straps during maneuvers before coming to the point where the straps or the sides of the cockpit restrain the torso from further lateral movement. Moreover, since the lateral straps allow some limited lateral movement of the torso, the sudden shock of the torso coming up against the straps and being abruptly decelerated thereby may also result in fatigue, bruising or some other injury to the pilot's torso. It must also be noted that in such a prior art restraint system, the chest straps do not make full contact with the sides of the pilot's torso because they are anchored to the seat at locations which are relatively far from the pilot's torso.
Some types of prior art pilot restraint systems use a chest strap whicn encircles the rib cage of the pilot. Such systems typically have the strap anchored to the seat at one point directly behind the center portion of the torso. Such prior art systems are used primarily to retain the pilot in a certain position relative to the seat. In such systems the attachment point of the strap to the seat may be a hook or latcn which restrains forward movement of the pilot's torso and whicn may also prevent the pilot's back from coming against the seat back during periods of hard acceleration. Sucn systems thus are relatively ineffective in protecting the pilot from forces of acceleration in the forward and lateral directions. Moreover, the pilot's ability to turn in the seat is seriously limited; since the straps are connected at one point behind the seat, the loop formed by the straps may swing about this point; however, it must also be noted that the pilot must swing within this limited range of movement in order for the straps to be able to restrain further lateral movement of the pilot. Consequently, since this system allows the pilot's torso to accelerate to a significant velocity during such swinging movements before being abruptly stopped, lateral forces may wrench the pilot's torso in a lateral direction. Thus, although this system allows the pilot to turn in the seat, it also allows the pilot's torso to swing laterally as a result of lateral forces of acceleration or deceleration. Therefore, reduction of the pilot's ability to turn in the seat is required in order to improve the system's ability to provide restraint against such lateral forces. Otherwise, lateral forces induced by aircraft maneuvers can result in violent lateral swinging of the pilot's body. Consequently, with this prior art system, the pilot's torso may become bruised or sustain other type of internal injury.
Other prior art systems require that the pilot be up against the back of the seat in order for restraint to be effective. Such prior art systems are directed to securing the pilot firmly against the seat; in any other position, the pilot may not be adequately protected from forces of acceleration or deceleration. As with other prior art systems discussed hereinabove, this prior art system typically may also provide lateral chest restraints which are anchored to the sides of the seat back. Thus, the straps used to restrain the pilot from lateral forces do not make full contact with the lateral torso of the pilot. As previously mentioned hereinabove with reference to other prior art systems, this lack of full contact allows lateral forces of acceleration or deceleration to move the pilot's torso up against the lateral strap. Such movement of the pilot within the restraint system can result in fatigue, bruising or serious internal injuries to the pilot. Moreover, because the pilot must be secured firmly to the seat in order for the restraining action to be effective, the pilot's movements are severely restricted. The pilot is not typically able to turn or bend over without releasing this type of prior art system. Thus, this prior art device has the disadvantage that it severely hampers the pilot's movements.
Other prior art systems may use inflatable bladders positioned at various points on the pilot's body to restrain the pilot and absorb the forces of acceleration or deceleration. Such systems commonly incorporate sensors to detect acceleration or deceleration forces. Typically, the sensors are electrically connected to a system of valves in nigh pressure tanks to inflate the bladoers at the appropriate instant. These systems tend to be inordinately complex and rely on the proper functioning of various mechanical, hydraulic or electrical components. A malfunction of any of these components may result in failure of the entire system; thus a malfunction of any of these components may result in a loss of all to restraining action. It must also be noted that the pilot must be flat up against the back of the seat in order for the restraining system to operate properly and to avoid injury to the pilot in the event of sudden acceleration or deceleration. The pilot is not able to turn in the seat or bend forward and still be able to rely on this particular type of restraining system to provide him safety. Thus, the pilot must be in a particular position relative to the seat in order for the restraining system to be effective.
Other prior art systems may provide lateral support pads on the seat back at a location just under the armpits of the occupant. These lateral support pads may have a wedge shape to conform to the contours of the human body. However, because of the wedge shape, the pads are best able to restrain the occupant from forces acting in a direction perpendicular to the inner surface of the pad. However, although the lateral pads are most effective at this angle perpendicular to the pad, lateral forces may instead act on the occupant at an angle which is oblique to but not perpendicular to the pad. Thus, severe lateral forces may tend to make the occupant slide off the lateral support pad. If, instead, there is a strap mounted between the forwardmost corner of one pad and the forwardmost corner of the other pad, the occupant may be adequately restrained between the pads, and the occupant will not slide off the lateral support pad; instead, the lateral force may tend to push the occupant's body into the connection point between the lateral support pad and the strap. Unfortunately, this is the point at which there is the least amount of padding at the lateral support pad. Moreover, since the pads are not adjustably mounted on the seat, in order to be properly effective these pads must be custom fitted to each particular pilot. In addition, this type of prior art system does not allow the occupant mobility; rather, the occupant must bend forward or turn around at the expense of losing the benefits of the system as a safety restraint.
Other prior art systems use a loop made up of two straps to restrain the torso of an occupant of a seat. The straps are connected together by means of a ring, and one strap extends out of a slit in the loop. One strap extends from the ring to the back of the seat and the other strap extends out of the aperture in the loop to the back of the seat at the other side. Both straps may either be connected together behind the seat or may be connected to appropriate anchoring positions on both sides of the seat. Turning movements of the occupant will cause one of the straps to be pulled out of the ring and the other strap to be pushed into the aperture, or vice versa. It is important to note that either strap may bind upon being pulled out of the ring or upon being pushed into the aperture. A disadvantage of this system is that this binding may cause the loop to become enlarged or constricted or may prevent further turning movements of the occupant. Thus, the operation of this system is not smooth and may instead hamper the turning movements of the occupant. Moreover, with this type of system, the occupant is not able to bend forward in the seat.
Another prior art system incorporates a pair of laterally positioned panels. These panels are rigid and are placed adjacent lateral portions of the occupant's torso. The seat thereby takes on a generally U-shape. The width of the lateral panels may be adjustable. However, the occupant is typically not completely restrained within the seat because the panels are required to project outwardly from the seat and do not envelop the occupant's torso. There are also no restraining elements preventing forward movement of the occupant in the seat. Thus, although the occupant is able to turn and bend forward in this type of prior art system, he is not adequately restrained from forces acting in the direction of the aircraft. Thus, although this type of prior art system provides mobility to the occupant, it does not provide proper restraint from forces acting in 2 or 3 dimensions. As with some of the other systems discussed hereinabove, this system has the disadvantage that the pilot must be flat against the seat back in order to prevent bruising or other injury to the occupant resulting from lateral forces of acceleration or deceleration.
Other prior art systems provide a limited degree of restraint against lateral forces through the use of shoulder straps. However, the use of shoulder straps also reduces the mobility of the occupant within the seat. Thus, the occupant is not able to turn or bend forward in the seat. It is also crucial to note that restraint against lateral forces is provided at the neck of the occupant. Upon the application of severe lateral forces of acceleration or deceleration, this restraint system will transmit these forces to the neck. Consequently, the disadvantage with this type of system is that the application of these forces to the neck can result in severe stresses being placed on the neck of the occupant. These forces can cause serious damage to the neck of the occupant. Therefore, a disadvantage of this type of system is that it can result in serious injury to the occupant. For a more complete analysis of fighter pilot shoulder restraint systems with particular emphasis on lateral restraint requirements, see the report by Van Patten, R. C., et al,: "Evaluation of AFTI/F-16 Restraint Concepts in the .+-.2y Environment," Air Force Aerospace Medical Research Laboratory, AFAMRL-TR-807130, Wright Patterson Air force Base, Ohio, October 1980.
Another prior art restraint device uses acceleration sensors to activate a system to restrain the occupant upon sensing forces of acceleration or deceleration which exceed a threshold value. One disadvantage with these systems is that upon detection of severe forces these straps are merely locked in position at the instant at which the forces are sensed. However, at the time of a crash, the occupant may not be in the proper position in the seat to provide maximum or even adequate restraint. In addition, this type of prior art system is typically rather complex and therefore has many component parts which are each capable of malfunction. Consequently, this system is inherently more unreliable than less complicated systems.
A restraint system is thus needed that will provide restraint against lateral as well as forward or backward forces of acceleration and deceleration while still affording the occupant translational and rotational mobility within the seat.